Polyesters of 3-hydroxy-4(phenylcarbonyl) phenoxyacetic acid and organic plastics stabilized therewith



violet lightl 1 L :J qf ltisxanother object of thisinvention to United States Patent O POLYESTERS OF 3-HYDROXY-4(PHENYLCAR- BONYL)PHENOXYACETIC ACID AND OR- GANIC PLASTICS STABILIZED THEREWITH Gerald R. Lappin, Kingsport, Tenn., assignor to Eastman Kodak Company, Rochester, N .Y., a corporation of New Jersey This-invention relates to a new group of compounds that have particular utility for stabilizing organic plastic materials normally subject to photodegradation. Preferred embodiments of the invention concern the stabilization of poly-a-olefin compositions, particularly polyethylene compositions, as well as cellulose acetate compositions and polyesters of 1,4-cyclohexanedimethanol and terephthalic acid.

Many common organic plastic materials of commerce are subject to photodegradation. Photodegradation of organic plastic materials is evident by telltale properties which are imparted to the particular plastic material such as change or acquisition of odor or color, surface cracking, brittleness, loss of dielectric properties, loss of tensile strength, and other properties delcteriousjto the utility of the organic plastic material. Accordingly, it iscommon practice to incorporate into organic plastic materials subject to photodegradation various materials to retard orinhibit the formation of such undesirable properties.

Various derivatives of 2-hydroxybenzophenone are known to be effective light stabilizers for many plastic compositions. However, many commercial additives of this type have disadvantageous properties and limited utility. In particular, many derivatives of 2-hydroxybenzophenone are not sufliciently compatible with such plastics as po lyethylene, for example, to allow their use in this 7 medium. Another disadvantage isthe relatively low molecular weight of commercial derivatives 'of 2-hydroxybenzophenone, these molecular weights generally range from about 200 to 250. Such additives to fibers and thin films of plastic materials are particularly susceptible to volatization and leaching. The compound, 4-dodecyloxy- 2-hydroxybenzophenone,"has a higher molecular weight a and has compatibility with polyethylene. However, this compound is still of relatively low molecular weight and the stabilizing 2-hydroxybenzophenone moiety has been substantially diluted by thellong-chain alkoxy radical attached thereto. Accordingly, it would be highly desirable to have a relatively high molecularweight' compound having the 2-hydroxybenzophenone'moiety diluted to a minimum degree.

It is an object of this invention to provide anew group j of compounds suitable for stabilizing organic plastic materials normally subject to'photodegradation.

It is another object of this invention to provide a novel group of relatively high molecular weight stabilizers for organic plastic materials, which stabilizers contain the 2- hydroxy benzophenone moiety diluted to a minimum degree. r o p It is another objectof this invention to provide novel compounds having a plurality 2-hydroxybenzophenone moietiesl 2" It-is anotherjob ect of this invention to provide novel poly-a-olefin compositions oft improved st'abilityto ultraprovide novel n ma 2,983,708 Patented May 9, 19 61 deactivators of ultraviolet light that are compatible with normally solid polyethylene compositions. I

It is another object of this invention to provide new normally solid cellulose acetate compositions of improved stability to ultraviolet light.

It is another object of this invention toprovide new compositions comprising polyesters of 1,4-cyclohexanedimethanol and terephthalic acid of improved stability to ultraviolet light.

It is likewise an object of this invention to provide novel normally solid, organic plastic materials in fiber and thin film form containing a stabilizer resistance to volatization and leaching therefrom.

Other objects of the invention will be apparent from the description and claims which follow; i

The novel compounds of the present invention are hydroXyl-containing esters having the following structural formula: l

OH o 0 l 0 XQiiQOQEno R wherein X is hydrogen or a lower alkoxy radical having 1 to 4 carbon atoms, R is a polyvalent aliphatic radical derived from a primary or secondary polyhydric alcohol and nis an integer of at least 2 and not more than the number of hydroxyl radicals of the polyhydric alcohol. The compounds of the invention can be prepared from 2,4-dihydroxybenzophenone and 2,4-dihydroxy-4'-alkoxybenzophenone by reacting an alpha-halogen acetic acid with the2,4-dihydroXybenzophenone compound to form 3-hyd roxy-4-(phenylcarbonyl) phenoxyacetic acid or 3,- hydroxy-4-(4-alltoxyphenyl-carbonyl) phenoxyacetic acid, which acid is then esterified with a polyhydric alcohol to produce the present esters. This series of reactions can be illustrated by the following equation: y

The 4 hydroxyl group of the 2,4-dihydroxybenzophenone compoundis typically ,esterified with .an equal mole proportion of .ch loroacetic acid by refluxing in acetone for abou tf12 hours in the presence of about a'half mole proportion of-potassiumcarbonate. The resulting 3-hydroioj- I l-(phenylcarbonyly phenoXyaceticacid or 3-hydroxy -4-(4- alkoxyphenylcarbonyl) phenoxyacetic acid is then-.este'rified with a suitable-polyhydric'alcoholgia typical reaction Suitable aliphatic polyhydric alcohols an in areas ingfthe present esters have 2 to-l0 carbon atoms and contain; '2 to 6 and Su'itable Jpolyhydric Rjiisf an I period being about? hours at a temp er atureof 200 to preferably: 2 to 4 hydroiryl groups J alcohols have the formula,"R(0H)" parad seme o a i The present: stabilizers can;

carbon, having 2 to 10 carbon atoms and nis an integer of from 2 to 6. Preferably all of the hydroxyl radicals of, the subject polyhydric alcohols are primary alcohols. However, alcohols containing secondary hydroxyl radicals can also be used. Alcohols containing tertiary hydroxyl radicals are not employed in the'preparation of the presentcompounds. Typical polyhydric alcohols that can be employed in the preparation of the present esters are 1,2-ethanediol, 1,3-n-propanediol, 1,4-n-butanediol, 1,5-npentanediol, 1,10-n-decanediol, l,3-diol-2,2-dimethylpropane, and related hydrocarbon diols of the formula I-IO(R) OH, as well as glycerol, sorbitol, 2,2-dihydroxyethyl ether, pentaerylthritol, l,4-cyclohexanedimethanol, and related primary and secondary polyhydric alcohols having 2 to 10 carbon atoms and 2 to 6 hydroxyl radicals.

In preparing the present compounds the hydroxyl radical in the 2-position ofthe benzophenone moiety remains unesterified. The molecular weight of the present compounds depends upon the nature of the polyhydric alcohol employed, polyhydric alcohols containing larger numbers of hydroxyl radicals can be used to prepare the higher molecular weight compounds. For example, an ester prepared from pentaerythritol, which contains 4 hydroxyl radicals, and 3-hydroxy-4-(phenyl carbonyl) vphenoxy acetic acid could be a compound containing one moiety of this alcohol and 4 moieties of this phenoxy acetic'acid derivative if the alcohol is fully esterified. The esters of the invention are either diesters or polyesters or mixtures thereof. The simplest compound of the invention is an ester of 3-hydroxy-4-(phenyl carbonyl) phenoxy acetic acid and 1,2-ethanediol, this compound having a molecular weight of about 570. Hence,- thecompounds' of the invention have molecular 'weights of at least 570 and generally molecular weights in the range of 570 to about 1500 or higher depending upon the nature ofithe polyhydric alcohol, the degree of iesterificatiomand the'substituent in the 4' position'in "the Z-hydroXybenZophenone moiety. j The present hydroxybenzophenone esters have utility as stabilizers for normally solid organic plastic materials normally'susceptible to photodegradation such as results on exposure to sunlight or ultravoilet: light. Typical of the organic plastic materials that canabestabilized with the esters of the invention include cellulose acetate, cellulose acetate butyrate, polyvinyl chloride, poly (1,4- cyclohexanedimethano'l 'terephthalate), polymethyl methacrylate, polystyrene, poly-a-olefins and related organic plastic materials normally .susceptible to photodeg'radw. 7 tion; Thepresentf stabilizers haveparticular utility as ultraviolet stabilizers :for' normally solid poly-a-olefins,

such as polyethylene,polypropylene, poly-4-methylpenpoly-a olefin's'prepared from normally gaseous aliphatic u-monoolefinic hydrocarbons containing 2 to-l-carbon atoms. p I t The subject ester stabilizers are of special interest for the stabilization of'normally solid polyethylene compositions such as are used in preparingi thin films and which have average molecular weights of 'at least 15,000 and stabilizers that are eifectivefor other well known polymers, resins and polyesters arednefieetive in polyethylene due 'to their incompatibility therewith. For example, if 2,4 -dihydroxybenzophenone is compounded in polyethylene .ateven .a 0,5% byweig-ht level, exudation ofthe 12,4-dihydroxybenzophenone begins at once and athe sujrfface'of the-polyethyleneiscoveredwith ai'film ofthe 'i y the additivein a very short while. j

nge. of proportions-{ o stabilize '4 weight are usually used in most organic plastic. mate: rials, with about 0.01% to 10% by weight being generally used in most organic plastic materials, and with amounts of from about 0.5% to 2.5% by weight being preferably used in polyethylene.

The present stabilizers can be incorporated into organic plastic materials. by conventional .methods, the methods used varying with the organic plastic material being stabilized. The stabilizer can be incorporated into the various plastic substrates by dry blending, melt blend: ing, deposition from solvent, milling on heated rolls and related conventional methods commonly used for blending and incorporating stabilizers into organic plastic materials.

As noted above-,,th e presentstabilizers have higher molecular weights than conventional 2-hydroxybenzophenone stabilizer compounds. Such higher molecular weights lend. tothe present. staibilizers reduced volatility and reduced susceptibility to leaching from plastics. as compared with known Z-hydroxybenzophenone com! pounds. Furthermore, the higher molecular weight of the present compounds'is obtained without a substantial reduction of the effective 2-hydroxybenzoph'enone moiety with an inert. long-chain.v Thus, on a weight-basis, the stabilizers of the invention are more effective than previously disclosedistabilizers containing. a 2-hydroxybenzophenone moiety. For example, the Z-hydroxybenzophenone stabilizingmoiety of the effective polyethylene stabilizer, 4-dodecyloxy hydroxybcnzophenone, comprises only 53% by weight of this compound, while the present stabilizer compounds contain up to about 70% by tene, poly-3-methyl-butene-l and other normally solid weight of the effective 2-hydroxybenzophenone stabilizing moiety. Hence, the-stabilizers of the invention have relatively high molecular weightsv which lend to them greater permanence in. normally solid organic plastic materials, and which permanence is attained without a dilution of stabilization properties.

The invention is illustrated by the followin examples of preferred embodiment. thereof. 1

EXAM PILE 1' Several. typical Z-hydroXybenZopIienone-containing' es ters vof the. inventionfwere prepared by reacting a't least a two mole proportion of. an acid having the formula: V

p V I 4 v C -jc "common-*5 wherein X was hydrogen or methoxy, with a: one mole proportion of a polyhydric alcohol, the "number ofmole proportions of acid being equal to the number of hydroxylradicals in the alcohol; The reactants were heated at about 200 C.'for two hours. and thereafter the temperature of the reaction mixture was'raisedto 250 C. and the reactants allowed to reactfor l5 moreminutes. The resulting reaction mixturev was then cooled to room' temperature andithe solid v.2-hydroxybenzophenone-containing esters recrystallized from a 50%-'50% acetone-methanol mixture. The resulting products had the following formula: V V a v .eemployed in atw'id'e T organic plastic materials 5} a ent?. fiqtqd rad t a; he pt'imumiat gumll te t- 3 i h U9 r tti u n pla tic materiali'beinglstabilized.

" Amounts o the present stabilizer of, at'least 0.01% by Table 1 Carbon-hydrogen analysis X n R M.P.,o. Calcd. Found O,perlELper- O,per- H,! ercent cent cent cent 11 -o 1110114- 148-150 61. 4 4. 57 61. a 4. 40 n. onlontonr- 131-133 68.3 4.83 66.4 4.01 n- -CH4gCH1)2-OH2- 123-125 66.4 5.02 68.3 5.08 H. CH4 emu-om- 114-116 66.6 5.22 68.5 5.17 H. -o H2(0H2)r-OHr- 120-124 10. o 6. 69. 9 6. 10 E (-CHH1)10 126-128 66. 6 4.60 66.3 4.02 H 2 -H=0O0Hr- 140-142 10.0 6.53 69.8 6.61

2 -om- -on,- x a 68.6 5.22 66.1 6. 1

H 3 -oH6-bn-on6- 61.6 4.46 61.2 4. 2

GHQ-

ti 4 -oH,- -om- 61.6 4.51 61.2 4.41

. CHT CHSO 2 -CH2CH2- 112-115 64.6 4.16 64.7 413 01110... 2 -CHz(CH2 31cHI- 132-136 66.0 6.66 65.8 634 GHQ-1 1 onto... 4 --on,-- -oH, 66.0 8.92 64.8 4.01

i 1 Obtained as a very viscous liquid.

{Obtamed as an amorphous solid, 1

.The above prepared esters were tested as stabilizers invention employed to acquire thcjdataf set out in Table against photodegradation in several normally solid or- 2 can be represented by the following formula: ga nic pl astic materials." Examples illustrating such a 40 for these esters is set out in Examples 2 to 4.

11 h 1 oono- -R EXAMPLEZ A. Polyethylene samples containing several of the ester stabilizers of the invention, as well as sampleszcontaining 1 Table .no additive and 2,4 dihydroxybenzophenone for comparative purposes, were subjected to an outdoor weathering 1 {messiah 1 test. The various. additives were incorporated. into poly- Wbwyl h xudacontent ethylene havmg an average molecular weight of about Additive tron after 10 27,600 and a density of 0.919 at a concentration of about 9 1 2 7 a gff fg 21% by weight of the polyethylene. bymilling on .heated a 61 1mm; .rollers in accordance with usual practice. Thereafter Ti the polyethylene was compression moldedinto sheets mils .thickJfiySamples of the resulting sheetsqcontaining the various additives and the control sample containing %:ggz0m, 11:2-

NODB l h 212 no additive were exposed to outdoor weathering on a XzH, ES QQ E E ZZ 8:3 0 0 of the various samples was :determined before exposure CH6 H and after 10 weeksof expos reby-rueasurenienf of in- RzmomqLcHhmzzuur M frared absorpuon 1n the 5.82,u reg1on. An arbitrary 1 1 carbonyl unit was givento the carbonyl increase for l h l comparative purposes. The determination of thecari *bonyl increase gives anearlyand reliable indicatiomof '9 photo-oxidation in poly-a-olefins. -Thecarbonyl increase 1 in-the resulting samples is set out in Table 2 below. E? 1 I l Reference is madeto the following two publications con- X=H' 3 ""7 -:"r"---" "r -r" -I -9 cernin'g the-determination of jcarbonyl' coii'tent by-in!- Ha ,t a' measurements: Rugg Smith an'd Bacon, .'1=61y- X50320; n=-on on,-,.n= "66-1.- r Sci. ,"l3,535 (i954) and Cross, Richards andWil lis, i r cussion's Faraday'Soc. No. 9,235 (1950) "Addition i. 1 v ally, the ai'nount ofexudationof :qhejvar'igiusjladditives, k 'QFf" 7"" indicatingth'ecompatibilitythefeofi in polyethylene, was :3 z-

c'eellu seiaeeta etih B. As noted above, the stabilizers of the invention are all compatible with polyethylene. Such compatibility with polyethylene is not shared by many other conventional stabilizers containing the Z-hydroxybenzophe'nohe moiety. Several stabilizers at a 1% by Weight level were incorporated into polyethylene by milling on heated rollers, compression molded into 60 mil sheets of polyresulting mixture-was" spun from the acetone into about 55 denier fibers. The resulting fibers, as well as comparable fibers containing no additive, were exposed' for 300 hours in a modified Atlas Twin-Arc Weather Ometer ethylene and exposed to outdoor weathering as described above. After the exposure to the weathering, the surfaces of the respective samples were examined for possible exudation of the stabilizer additive, Table 3 below summarizes the results of the compatibility tests' of the various 2-hydroxybenzophenones in the polyethylene samples.

Table 3 Additive Exudation 2,2,4,4-tetrahydroxybenzophenone Much. 2,2-dihydroxy-4, 4-dimethoxybenzophenone Do. 2,4-dihydroxy-fi-n-hexylbenzophenone.. Do. 2-11ydroxyi,4-dimethoxybenzophenone Do. 2-hydroxy-fi-methylbenzophenone Do. 2,4-dihydroxy-5-n-dodeeyloxybenzopheuone D0.

7 EXAMPLE 3 A polyester was prepared by reacting a 0.6 mole proportion of dimethyl terephthalate, a 0.2 mole proportionj of succinic anhydride and a 1.0 mole proportion of 1,4

cyclohexane dimethanol in accordance with the method described in Example 1 of copending Kibler application,

U.S; Serial No. 554,639, filed December 22, 1955, now US. Patent No. 2,901,466. Several samplestof the result- OH I:

Table 5 h Retention of original Additive tensile t strength;

Percent None. Q 42 X=H, R= -CHa(GHa);CHr, 11:2 s5

x=n, n;-oH'e+oj-orn-, 11:4 .89

X.=-"CH30IR;-CH2(CH2)3-CHz-, 'n =2 T. H 8 6 ing polyester and several stabilizers of the invention at a 1% by weight level based on the polyester were dissolved I in tetrachloroethane and 3 mil films were cast from this dope. T he resulting films were then cut into approxi mately 2 /2 by /z i'n ch samples and exposed for varying lengths of =time-in an Atlas-Twin-Arc Weather-Ometer described in Anal. Chem, 25, 460 (1953) that was modified by the addition of 12.W estinghouse 2Q-watt fluorescent sun lamps.-; Exposure damage was ,evaluatedby observing fwhen cracking and::complete breaking resulted on creasingfthe samples. Theresults. are summarized, on Table 4 below. The stabilizers of the invention employed. to acquire. thev data. settout in' Table 4 can be I represented by the following formula: V

I L Several of the hyd'rbxyl containing esters of the invenftion were tested as stabilizers in cellulose acetate fibers. '.-The-various stabilizers were addedat .a level of 1% by weight based on the weight of thecellulose acetate, the

rinsaaacetyl co e o ab 39% .;-1 1 by weight, in an" cetone dope thereof. Thereafter, the" as describedinEXample 3 above. The tensile strengths of the resulting fibers Were determined after exposure and compared with the original tensile strengths before exposure. The results are summarized in Table 5 below in terms of percent of original tensile strength retained. The stabilizers of the invention employed to acquire the data set out in Table 5 can be represented by the following formula:

7 Thus, the present invention provides a new and useful group of 2-hydroxybenzophenone-containing esters. These novel esters are effective stabilizers for organic plastic materials normally subject to photodegradation. In addi tion, the Z-hydroxybenzophenone-containing esters of the invention canbe prepared in relatively high molecular weights with a minimum of dilution of thefZ-hydroxy enzophenone' moiety. Suchesters, because oftheii molecular'weights, have greater permanence" in normally solid organic plastic materials than conventional 2-hy-;

droxyben'zophenones.

Although the 'inv'ention'fhas 'b'een des'crib'ed in detail' with reference, to certain preferred embodiments thereof,

it wili be understood that'variations and modifications can .b'eeffecte'd withinithe spirit andscope of the invention as "described hereinabov'e and" as defined irithe appended 'claims. i lelairnt- V 1 1. A composition of'rna-tier comprising'anormally solid organidplastie-material normally susceptible to photodegradation containing dispersed therein at least-.0l% *by weight of ahydr'oxyl containing ester having th'e'formul'a:

OH 7 t wherein'Xi's'selectedfrom the groupconsisting oflhydro-v i. "genland lower alkoxyradicals having 1 to 4. carbon atoms, 'R'is: aipolyvalent aliphatic radical having 2 to 1Q carbon .the, group consistingof primary alcohols andsecondary alcohols having 2 m; 6'hydroxy,radicals,' and n isan, in-

.teger equalnto the number of hydroxyl radicals of; said polyhydricyalcohol.v

2 7A co'mpositioniof matter 'as de scribed' in claim-g1 V .wherein the'polyhydricalcohol is selected from the group consisting. of 1,2-etha nediol", 1,3 -r 1I-propan ediol, 4-

hutanediol, ;1,5-in-pentane diol, 1',l n-decanedio h ethanol, glycerol, 2,2-dihydroxyethy -d1 ol'-2,Zdmethylpropane and: pentaerythritol;-

Alcoiiiposition -as"de's'cribed in claim l where organic plastic material is cellilldse i'ace't'a t alcohols having 2 integer equal to thenumber of hydroxyl radicals of said 9, 4. A compositionas described in claim 1 wherein the organic plastic material is a polyester of 1,4-cyclohenanedimethanol and terephthalic acid. I

"15. 'A composition as described in claim 1 wherein the organic plastic material is a poly-a-olefin composition.

6. A composition as described in claim 1 wherein the plastic material is polyethylene. I t '7. A composition of matter comprising a normally solid organic plastic material selected from the group consisting of polyethylene, cellulose acetate and a polyester of 1,4-cyclohexanedimethanol and terephthalic acid, containing dispersed therein .01% to by weight of a hydroxyl-containing ester having the formula:

wherein X is selected from the group consisting of hydrogen and lower alkoxy radicals having 1 to 4 carbon atoms, R is a polyvalent aliphatic radical having 2 to 10 carbon atoms and derived from a polyhydric alcohol selected from the group consisting of primary alcohols and secondary alcohols having the formula R(OH) and n in the said hydroxyl-containing ester formula and n in the said polyhydric alcohol formula are integers of 2 to 4 and are equal integers.

8. A hydroxyl-containing ester having the formula:

QMb l wherein X is selected from the group consisting of hydrogen and lower alkoxy radicals having 1 to 4 carbon atoms,

10 "11.'A composition of matter comprising a normally solid organic plastic material normally susceptible to photodegradation containing dispersed therein .01% to 10% by weight of a hydroxyl-containing ester having the formula:

[Q Q -L wherein R is a polyvalent hydrocarbon radical having 2 to 10 carbon atoms and derived from a polyhydric primary alcohol having the formula R(OH) and n in the said hydroxyl-containing ester formula and n in the said polyhydric primary alcohol formula are integers of 2 to 4 and are equal integers.

13. A hydroxyl-containing ester having the formula:

[QEOHQME-O-L wherein R is a divalent hydrocarbon radical having 2 to 10 carbon atoms and derived from a primary dihydric alcohol.

14. A hydroxyl-containing ester having the formula:

R is a polyvalent aliphatic radical having 2 to 10 carbon 15. A hydroxyl-containing ester having the formula;

OH OH o 0 CH: (I?

t@-oc ioCHsCEOCWQCQ atoms derived from a polyhydric alcohol selected from the group consisting of primary alcohols and secondary to 6 hydroxyl radicals, and n is an polyhydric alcohol.

9. A hydroxyl-containing ester as described in claim 8 wherein the polyhydric alcohol is selected from the group '55 consisting of 1,2-ethanediol, 1,3-n-propanediol, 1,4-n-

butanediol, 1,5-n-pentanediol,

LlO-n-decanediol, 1,4 cyclohexanedimethanol,

glycerol, 2,2'-dihydroxyethyl ether, l,3-diol-2,2-dimethylpropane and pentaerythritol.

'10. A composition of matter comprising a normally solid organic plastic material normally susceptible to photodegradation containing dispersed therein .0l% to t 10% by-weight of a hydroxyl-containing ester having the formula:

16. A hydroxyl-eontaim'ng ester having the formula:

a 'CHiO-R HO-R mo-a V wherein-R is a monovalent radical having the formula:

17; A-hydroxyl-containing ester having the formula: 4;

CHQOR ROHzC--CHzOR HgOR- wherein R is a'monovalent radical having the formulaz; v

18 A hydroxyl-eontaini ng ester having the formula: i t. H 0H moo ocmoogn a divalent hydrdcarbomhaving names atoms: and: derived from a primary dihydric i OTHER REFERENCES aloolidl'. I h Chevass'us: La Stabilisation Des Chlorures' De Poly- R'efyere'pcefsclted m'the file mls'patem' vinyl-,l copyright 1957', Les Editions Amphora, Paris,

UNITED STATES PATENTS 5 Francema-ggg 8Q- 8-7 D 2,811,461 Meyer etraL- Oct. 29, 1957 1 Beilsteinz- Handbuch Der Organischent ChemimYierte 2,831,768 Merrill Apr. 22, 1958 Auflage, vol. X, copygight-1927,pag 1042 i 

1. A COMPOSITION OF MATTER COMPRISING A NORMALLY SOLID ORGANIC PLASTIC MATERIAL NORMALLY SUSCEPTIBLE TO PHOTODEGRADATION CONTAINING DISPERSED THEREIN AT LEAST .01% BY WEIGHT OF A HYDROXYL-CONTAINING ESTER HAVING THE FORMULA: 